| Siew Seng Yeow | 5204 | Mechanical | 2019-03-21 | Building and Construction Authority |
| Siew Yee Cheong | 1885 | Mechanical | 1983-03-11 | Integrated Building Consultants |
| Sim Gim Leong Frankie | 4300 | Civil | 2009-03-19 | SGL Consulting Engineers |
| Sim Gim Lian | 4519 | Civil | 2013-06-13 | SGL Consulting Engineers |
| Sim Hong Sheng | 5506 | Electrical | 2023-01-26 | RES Engineering Pte. Ltd. |
| Sim Jin Sing | 4086 | Mechanical | 2006-10-17 | Defence Science and Technology Agency |
| Sim Kok Liang | 4472 | Civil | 2012-09-20 | Binnies Singapore Pte. Ltd. |
| Sim Kwai Meng William | 2397 | Civil | 1988-05-18 | A.WSim Consultancy |
| Sim Mui Leng | 3889 | Civil | 2004-05-05 | PH Consulting Pte. Ltd. |
| Sim Poh Hock | 4254 | Electrical | 2007-07-19 | CAG |
| Sim Soon Siang Simon | 3657 | Electrical | 2001-09-18 | PUB, Singapore's National Water Agency |
| Sim Teong Guan | 3692 | Electrical | 2002-03-19 | SP PowerGrid Limited |
| Sim Wee Ann | 5817 | Electrical | 2025-11-27 | Allied Power Pte Ltd |
| Sim Wee Beng | 4617 | Electrical | 2014-07-17 | - |
| Sim Wee Keat | 4672 | Civil | 2015-04-16 | - |
| Sin Kam Choi Joseph | 1321 | Civil | 1978-04-04 | Shincon Industrial Pte Ltd |
| Sin Kin Tzu | 4363 | Electrical | 2010-07-16 | United Project Consultants Pte Ltd |
| Sin Yew Tek | 4242 | Mechanical | 2007-06-14 | Land Transport Authority |
| Sindhu Tjahyono | 5763 | Civil | 2025-05-22 | WSP Consultancy Pte. Ltd. |
| Siong Tat Leong | 5722 | Civil | 2025-01-23 | CCCC-SJ Pte. Ltd. |
| Siow Chew Yong | 3894 | Mechanical | 2004-05-05 | J Roger Preston (Singapore) Pte Ltd |
| Sivagnanasundaram Sathiyanarayanan | 5661 | Civil | 2024-06-27 | Mott MacDonald Singapore Pte Limited |
| Sivakumaran Murugesu | 3493 | Civil | 1999-08-17 | SMS Consulting Engineers Pte. Ltd. |
| Sivakumaru Kandasamy | 4748 | Civil | 2016-02-16 | Aurecon Singapore (Pte.) Ltd. |
| Sivapalan Jasekan | 5810 | Civil | 2025-10-23 | T.Y.Lin International Pte. Ltd. |
| Sivapathakunam Pirashanth | 5781 | Civil | 2025-07-24 | WSP Consultancy Pte. Ltd. |
| Sng Chong How | 5867 | Electrical | 2026-03-26 | Tan Tock Seng Hospital (TTSH) |
| Sng Jiek Wai | 3056 | Electrical | 1994-08-17 | - |
| Sng Meng Liang | 4272 | Civil | 2007-08-16 | Green Cosmo Marketing P |
| Sng Wee Kwan | 4137 | Civil | 2007-02-23 | Vland Consultants Pte. Ltd. |